Patents older than age 65 represent 13 percent of the U.S. population, yet they receive more than 35 percent of all prescription drugs and disproportionately suffer adverse experiences from psychotropic medications. The critical gaps in our knowledge of appropriate pharmacotherapy for elders with psychiatric illness are exacerbated by the shortage of new investigators trained in geriatric clinical pharmacology. This K24 award addresses this important problem by supporting further career development for an established investigator in geriatric psychopharmacology and his mentoring of junior investigators in patient-oriented research. The overarching goal of this candidate's research program is to determine inter-individual pharmacokinetic and pharmacodynamic variables affecting treatment outcome as well as to specifically address the dearth of information regarding newer antidepressants and antipsychotics in elderly patients. The primary developmental goal during the proposed K24 award period is for the candidate to enhance his expertise in population pharmacokinetics using mixed-effects modeling. This builds on the current strengths of his research program, and represents a very significant enhancement by permitting more optimal utilization of sparse drug concentration data from clinical trials. The secondary developmental goal is for the candidate to deepen his knowledge of basic and quantitative genetics. Developmental activities will occur primarily in the context of the candidate's current R01 "Continuation Pharmacotherapy for Agitation in Dementia". The goal of this study is to improve the treatment of non-cognitive symptoms of dementia in severely affected patients. This protocol will test if the highly selective serotonin reuptake inhibitor (SSRI) citalopram and the atypical antipsychotic risperidone are differentially effective in ameliorating behavioral symptoms and/or psychosis particularly during continuing pharmacotherapy upon discharge from a hospital setting. The candidate also proposes to enhance his skills as a mentor by working closely with experienced medical educators. He will recruit at least two new trainees per year through three Departmental training grants with which he is closely associated. Trainees will be medical students, residents, post-doctoral fellows and junior faculty. Particular emphasis will be given to increasing recruitment of under-represented minorities. The applicant will mentor trainees in analyses of existing data as well as design and implementation of clinical studies. Success in mentoring will be judged by trainee's productivity in peer-reviewed publications and competition for career development awards and research funding.